Highly Sensitive NEMS Pressure Sensor From Bilayer Graphene

Graphene is an ideal candidate material for the fabrication of high-performance pressure sensors due to excellent mechanical strength and electrical conductivity. However, suspended bilayer graphene has rarely been studied for nano-electromechanical system (NEMS) pressure sensors. In this work, a suspended bilayer graphene-based NEMS pressure sensor with multiple cavities was realized. To improve the performance of the pressure sensor, a bilayer graphene membrane was used to ensure the integrity and hermeticity of the suspended membrane. Meanwhile, the arrays of cavities for suspending graphene membrane were designed to achieve as many intact suspended graphene membranes as possible. The sensitivity of the device was <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$3.4\times 10^{-{5}}$ </tex-math></inline-formula> kPa<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${}^{-{1}}$ </tex-math></inline-formula> in the pressure range of 50–100 kPa and was higher than the previous graphene-based pressure sensors. Furthermore, bilayer graphene-based NEMS pressure sensors were modeled and simulated. And the gauge factor of bilayer graphene membrane was estimated to be 4.3. This work would contribute to the development of next-generation ultra-small and sensitive 2-D NEMS sensors.